When you’re isolated on a project that’s not going very well it can be a very demoralizing experience. Things that don’t go well bring you down harder for a couple of reasons: you have no one to bounce ideas off of, and you also blame yourself for not doing the job right in the first place. I know it gets me into a very bad head-space.
The moment you have other people that are living in the same world, for better or worse, it’s a lot easier to get along. You have validation that the problems are hard and you start to bring new perspective to the obstacles that are run into.
All in all, it’s a big win. :-)